title: Fabrication of Mg alloy tubes for biodegradable stent application.
abstract: Though Mg alloys are promising candidates for biodegradable stents, it is very difficult to fabricate stent tubes with high dimensional accuracy using Mg alloys because of their low deformability. This study aimed to develop thin-walled, high-quality Mg alloy tubes with good performance in stent applications. Cold drawing with a fixed mandrel was carried out for extruded Mg-0.8%Ca and AZ61 alloy tubes using optimized drawing parameters and lubrication, and stent tubes with 1.5-1.8mm outer diameter and 150 μm thickness were fabricated. A dimensional evaluation showed that the tube dimensional errors were within 0.02-2.5%. Also, an immersion test of pure Mg with different crystal orientations showed that the crystal orientation affected the corrosion properties, results that are the same with other Mg alloys. The crystal orientation of the stent tube could be controlled by changing the deformation amount and direction in the drawing, showing that it is possible to further improve the biodegradability of stents by approaching their fabrication from a processing aspect.
authors.affiliation: Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan. Electronic address: hanada.k@aist.go.jp.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Hanada
authors.forename: Kunio
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Huang
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Chino
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D003343:Corrosion; D008274:Magnesium / Q000737:chemistry*; D015607:Stents
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D008274:Magnesium
keywords: Biodegradable stent; Corrosion; Dimensional accuracy; Magnesium alloy; Microstructure; Tube drawing